Maximum likelihood sequence detection in the phase domain

Abstract

A wireless device, and corresponding method, having a receiver configured to receive a signal having in-phase and quadrature components; a non-linear filter demodulator configured to translate noncoherently the in-phase and quadrature components into a phase domain signal; a coherence acquisition unit configured to estimate and correct at least one coherence parameter based on the in-phase and quadrature components and the phase domain signal; and a detector configured to detect information in the phase domain signal.

The invention claimed is: 
     
       1. A wireless device, comprising:
 a receiver configured to receive a signal having in-phase and quadrature components; 
 a non-linear filter demodulator configured to translate noncoherently the in-phase and quadrature components into a phase domain signal; 
 a coherence acquisition unit configured to estimate and correct at least one coherence parameter based on the in-phase and quadrature components and the phase domain signal; and 
 a coherent detector configured to detect information in the phase domain signal. 
 
     
     
       2. The wireless device of  claim 1 , further comprising:
 an estimator configured to estimate a modulation index of the received signal; and 
 an equalizer configured to equalize the estimated modulation index to a predefined modulation index. 
 
     
     
       3. The wireless device of  claim 2 , wherein the estimator is configured to perform a linear estimation technique for unknown linear coefficients. 
     
     
       4. The wireless device of  claim 2 , wherein the predefined modulation index is about 0.5. 
     
     
       5. The wireless device of  claim 2 , wherein the detector is a Maximum Likelihood Sequence Detector (MLSD). 
     
     
       6. The wireless device of  claim 1 , wherein the nonlinear filter demodulator is based on a model comprising a plurality of sets of variables. 
     
     
       7. The wireless device of  claim 6 , wherein the plurality of sets of variables comprise a set of auxiliary variables, a set of instantaneous frequency variables, and a set of instantaneous phase variables. 
     
     
       8. A wireless communication network comprising:
 a first wireless device, which is the wireless device of  claim 1 ; and 
 a second wireless device communicating with the first wireless device. 
 
     
     
       9. The wireless communication network of  claim 8 , wherein the wireless communication network is a low-power wireless sensor and actor network (LP-WSAN), the first wireless device is an actor, and the second wireless device is a sensor. 
     
     
       10. A method of wireless communication, comprising:
 receiving, by a receiver, a signal having in-phase and quadrature components; 
 translating noncoherently, by a non-linear filter demodulator, the in-phase and quadrature components into a phase domain signal; 
 estimating and correcting, by a coherence acquisition unit, at least one coherence parameter based on the in-phase and quadrature components and the phase domain signal; and 
 detecting, by a coherent detector, information in the phase domain signal. 
 
     
     
       11. The method of  claim 10 , further comprising:
 estimating, by an estimator, a modulation index of the received signal; and 
 equalizing, by an equalizer, the estimated modulation index to a predefined modulation index. 
 
     
     
       12. The method of  claim 11 , wherein the estimating by the coherence acquisition unit is linear estimation for a plurality of unknown linear coefficients. 
     
     
       13. The method of  claim 11 , wherein the predefined modulation index is about 0.5. 
     
     
       14. The method of  claim 10 , wherein the detecting step is performed using Maximum Likelihood Sequence Detection (MLSD). 
     
     
       15. A computer program product embodied on a non-transitory computer-readable medium comprising program instructions configured such that when executed by processing circuitry cause the processing circuitry to implement the method of  claim 10 . 
     
     
       16. A wireless device, comprising:
 a receiving means for receiving a signal having in-phase and quadrature components; 
 a non-linear filtering demodulating means for translating noncoherently the in-phase and quadrature components into a phase domain signal; 
 a coherence acquisition means for estimating and correcting at least one coherence parameter based on the in-phase and quadrature components and the phase domain signal; and 
 a coherent detection means for detecting information in the phase domain signal. 
 
     
     
       17. The wireless device of  claim 16 , further comprising:
 an estimating means for estimating a modulation index of the received signal; and 
 an equalizing means for equalizing the estimated modulation index into a predefined modulation index. 
 
     
     
       18. The wireless device of  claim 16 , wherein the detection means is a Maximum Likelihood Sequence Detector.